MTS Announces an ADR Ratio Change

MOSCOW, April 20, 2010 - Mobile TeleSystems OJSC ("MTS" - NYSE: MBT), the leading
telecommunications provider in Russia and the CIS, announces that it will be
changing its current American Depositary Receipt (ADR) ratio effective May 3,
2010.

The ratio will change from the current 1 ADR per 5 common
shares to 1 ADR per 2 common shares. Existing ADRs will continue to be valid
and will not have to be exchanged for new ADRs. The number of underlying
common shares will remain unchanged.

To implement the change, MTS ADR holders of record at the
close of business on April 28, 2010, will receive 1.5 ADRs for each ADR held.
Additional ADRs are expected to be distributed on or around April 30, 2010,
the ADR payment date.

Commenting on the ADR ratio change, Mikhail Shamolin,
President and CEO of MTS, said: "MTS' ADR price has increased more than 60%
since the Company's last effective stock split in January 2005. Changing the
ADR ratio will bring the price more in line with our peer companies and
support liquidity. We feel this will allow our ADRs to appeal to a broader
investor base and provide additional flexibility to current shareholders in
managing their portfolios."

Learn more about MTS. Visit the official blog of the Investor Relations
Department at www.mtsgsm.com/blog/

Mobile TeleSystems OJSC ("MTS") is the leading telecommunications group
in Russia, Eastern Europe and Central Asia, offering mobile and fixed voice,
broadband, pay TV as well as content and entertainment services in one of the
world's fastest growing regions. Including its subsidiaries, the Group
services over 102.3 million mobile subscribers in Russia, Ukraine,
Uzbekistan, Turkmenistan, Armenia and Belarus, a region that boasts a total
population of more than 230 million. Since June 2000, MTS' Level 3 ADRs have
been listed on the New York Stock Exchange (ticker symbol MBT). Additional
information about the MTS Group can be found at www.mtsgsm.com.

Some of the information in this press release may contain
projections or other forward-looking statements regarding future events or
the future financial performance of MTS, as defined in the safe harbor
provisions of the U.S. Private Securities Litigation Reform Act of 1995. You
can identify forward looking statements by terms such as "expect," "believe,"
"anticipate," "estimate," "intend," "will," "could," "may" or "might," and
the negative of such terms or other similar expressions. We wish to caution
you that these statements are only predictions and that actual events or
results may differ materially. We do not undertake or intend to update these
statements to reflect events and circumstances occurring after the date
hereof or to reflect the occurrence of unanticipated events. We refer you to
the documents MTS files from time to time with the U.S. Securities and
Exchange Commission, specifically the Company's most recent Form 20-F. These
documents contain and identify important factors, including those contained
in the section captioned "Risk Factors" that could cause the actual results
to differ materially from those contained in our projections or
forward-looking statements, including, among others, the severity and
duration of current economic and financial conditions, including volatility
in interest and exchange rates, commodity and equity prices and the value of
financial assets; the impact of Russian, U.S. and other foreign government
programs to restore liquidity and stimulate national and global economies,
our ability to maintain our current credit rating and the impact on our
funding costs and competitive position if we do not do so, strategic actions,
including acquisitions and dispositions and our success in integrating
acquired businesses, including Comstar-UTS, potential fluctuations in
quarterly results, our competitive environment, dependence on new service
development and tariff structures, rapid technological and market change,
acquisition strategy, risks associated with telecommunications
infrastructure, governmental regulation of the telecommunications industries
and other risks associated with operating in Russia and the CIS, volatility
of stock price, financial risk management and future growth subject to risks.

    For further information, please contact in Moscow:

    Joshua B. Tulgan
    Director, Investor Relations
    Mob: +7-985-220-4208

    Department of Investor Relations
    Mobile TeleSystems OJSC
    Tel: +7-495-223-2025
    E-mail: ir@mts.ru

For further information, please contact in Moscow: Joshua B. Tulgan, Director, Investor Relations, Mob: +7-985-220-4208; Department of Investor Relations, Mobile TeleSystems OJSC, Tel: +7-495-223-2025, E-mail: ir at mts.ru